android webview H5开发若干问题之问题一:webview文件上传问题

问题一：

         WebView文件上传问题。

        在安卓里webview加载的网页标签<input type=file/>上传是不成功的，需要重写WebChromeClient的openFileChooser和onShowFileChooser，才能实现文件标签功能。那么，为什么要实现两种不同名字的方法呢。下面将给出解答以及实现。

        在之前，实现openFileChooser的方法，重载此方法，参数不同，适应不同版本的安卓手机，对于绝大部分版本的安卓机子都没问题。但是自从出了LOLLIPOP，这个方式就在5.0的机子上不管用了，以至于如今的6.0手机。这是因为安卓5.0的新增的更新改进，增加了onShowFileChooser方法，在5.0以上版本手机可以使WebView 中使用输入表单字段和启动文件选择器从 Android 设备中选择图片和文件。

          上代码：

           重写WebChromeClient

           

import android.annotation.TargetApi;import android.app.Activity;import android.content.ActivityNotFoundException;import android.content.Intent;import android.net.Uri;import android.os.Build;import android.webkit.ValueCallback;import android.webkit.WebChromeClient;import android.webkit.WebView;import android.widget.Toast;/** *  */public class CustomWebChromeClient extends WebChromeClient{    private Activity activity=null;    private int FILECHOOSER_RESULTCODE=0;    private int REQUEST_SELECT_FILE = 0;    private ValueCallback<Uri> mUploadMessage;    public  CustomWebChromeClient(Activity activity,int FILECHOOSER_RESULTCODE,int REQUEST_SELECT_FILE)    {        this.activity=activity;        this.FILECHOOSER_RESULTCODE=FILECHOOSER_RESULTCODE;        this.REQUEST_SELECT_FILE=REQUEST_SELECT_FILE;    }    public void openFileChooser(ValueCallback<Uri> uploadMsg) {        if (activity.getClass()== MainActivity.class)        {            ((MainActivity)activity).mUploadMessage=uploadMsg;        }        mUploadMessage = uploadMsg;        Intent i = new Intent(Intent.ACTION_GET_CONTENT);        i.addCategory(Intent.CATEGORY_OPENABLE);        i.setType("*/*");        activity.startActivityForResult(Intent.createChooser(i, "文件选择"), FILECHOOSER_RESULTCODE);    }    // For Android 3.0+    public void openFileChooser( ValueCallback uploadMsg, String acceptType ) {        if (activity.getClass()== MainActivity.class)        {            ((MainActivity)activity).mUploadMessage=uploadMsg;        }        mUploadMessage = uploadMsg;        Intent i = new Intent(Intent.ACTION_GET_CONTENT);        i.addCategory(Intent.CATEGORY_OPENABLE);        i.setType("*/*");        activity.startActivityForResult(                Intent.createChooser(i, "文件选择"),                FILECHOOSER_RESULTCODE);    }    //For Android 4.1    public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture){        if (activity.getClass()== MainActivity.class)        {            ((MainActivity)activity).mUploadMessage=uploadMsg;        }        mUploadMessage = uploadMsg;        Intent i = new Intent(Intent.ACTION_GET_CONTENT);        i.addCategory(Intent.CATEGORY_OPENABLE);        i.setType("*/*");        activity.startActivityForResult(Intent.createChooser(i, "文件选择"), FILECHOOSER_RESULTCODE );    }    // For >= Lollipop 5.0    @TargetApi(Build.VERSION_CODES.LOLLIPOP)    public boolean onShowFileChooser(WebView mWebView, ValueCallback<Uri[]> filePathCallback, WebChromeClient.FileChooserParams fileChooserParams) {                    if (((MainActivity) activity).uploadMessage != null) {                ((MainActivity) activity).uploadMessage.onReceiveValue(null);                ((MainActivity) activity).uploadMessage = null;            }            ((MainActivity) activity).uploadMessage = filePathCallback;                Intent intent = fileChooserParams.createIntent();        try {            activity.startActivityForResult(intent, REQUEST_SELECT_FILE);        } catch (ActivityNotFoundException e) {            ((MainActivity) activity).uploadMessage = null;            Toast.makeText(activity.getApplicationContext(), "不能打开文件选择器", Toast.LENGTH_LONG).show();            return false;        }        return true;    }}               MainActivity代码：
import android.app.Activity;import android.content.Intent;import android.net.Uri;import android.os.Build;import android.os.Bundle;import android.view.KeyEvent;import android.webkit.ValueCallback;import android.webkit.WebChromeClient;import android.webkit.WebView;import android.widget.Toast;public class MainActivity extends Activity {      public ValueCallback<Uri> mUploadMessage;    public final static int FILECHOOSER_RESULTCODE=1;    public ValueCallback<Uri[]> uploadMessage;    public static final int REQUEST_SELECT_FILE = 100;    private WebView  webView;   @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);       webView = new WebView(this); 
      webView.getSettings().setJavaScriptEnabled(true);
      webView.setWebChromeClient(new CustomWebChromeClient(activity, FILECHOOSER_RESULTCODE,REQUEST_SELECT_FILE));       setContentView(webView);    }    @Override    public boolean onKeyDown(int keyCode, KeyEvent event) {        if (keyCode == KeyEvent.KEYCODE_BACK) {            if (webView .canGoBack()) {                webView .goBack();                return false;            } else {                return super.onKeyDown(keyCode, event);            }        } else {            return super.onKeyDown(keyCode, event);        }    }    @Override    protected void onActivityResult(int requestCode, int resultCode,                                    Intent intent) {        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)        {            if (requestCode == REQUEST_SELECT_FILE)            {                if (uploadMessage == null)                    return;                uploadMessage.onReceiveValue(WebChromeClient.FileChooserParams.parseResult(resultCode, intent));                uploadMessage = null;            }        }        else if (requestCode == FILECHOOSER_RESULTCODE)        {            if (null == mUploadMessage)                return;            Uri result = intent == null || resultCode != MainActivity.RESULT_OK ? null : intent.getData();            mUploadMessage.onReceiveValue(result);            mUploadMessage = null;        }        else {            Toast.makeText(this.getApplicationContext(), "Failed to Upload Image", Toast.LENGTH_LONG).show();        }    }}      以免扰乱阅读，本例子仅仅单纯的解决的文件标签的问题。 

  github地址：https://github.com/xiaoyunchengzhu/AndroidAndH5